Palate development in mice is being studied by releasing the fetus from the uterus and membranes into a fluid medium without severing the umbilical cord. Fetal movements are timed after administration of a variety of cleft palate teratogens to see whether the latter have affected functioning of the fetal neuromuscular system in a manner measurable by this technique. Excision of the fetal tongue is performed to test the ability of palatine shelves to fuse after this obstacle has been removed. The morphology of fusion under such conditions is being compared to in utero fusion, using transmission electron microscopy. BIBLIOGRAPHIC REFERENCES: Walker, B.E. and J. Quarles 1975. Embryonic movements during palate development with anti-inflammatory agents. J. Dent. Res. 54:1200-1206. Walker, B.E. and J. Quarles 1975. Palate development in mouse embryos after tongue removal. Archs. Oral Biol. (in press).